1. Field of the Invention
This invention generally relates to a bicycle front derailleur. More specifically, the present invention relates to a bicycle front derailleur having a biasing arrangement operatively disposed between a base member and a movable member that regulates the operating force for shifting the movable member.
2. Background Information
Generally, a front derailleur is mounted to the bicycle frame adjacent to the front chain rings to shift a chain laterally between the front chain rings. A front derailleur includes a fixed or base member that is non-movably secured to the bicycle frame, and a movable member. The movable member includes a chain guide that is movably supported relative to the fixed member to move between at least two lateral shift positions. Typically, a linkage assembly is coupled between the fixed member and the movable member in order to movably support the movable member with the chain guide. The chain guide typically has a pair of cage plates or guide plates arranged to selectively contact and move the chain between the front chain rings. The chain guide is usually moved relative to the base member against a biasing force of a spring by pulling and/or releasing a shifter control cable that is coupled between a shifter and the front derailleur. The control cable is often connected to one of the pivotal links to apply a torque thereto in order to move the chain guide between an extended position and a retracted position. Two examples of cable operated front derailleurs are disclosed in U.S. Pat. Nos. 6,093,122 and 7,081,058.